1. Field of the Invention
The present invention relates to improvements in such a washer pump that is used to supply a liquid for washing windows in a vehicle.
2. Description of the Related Art
FIG. 17 shows part of a vehicle window washing system disclosed in Japanese Utility Model Publication No. 48-30906: FIG. 17A is a front view of the washing system and FIG. 17B is a side view of the same system, partially broken.
The vehicle window washing system comprises a tank 1 including a side recess 3 which is formed in the tank 1 at one side for receiving a pump part 2 tightly therein. The outer opposite edges of the side recess 3 include projections 4 for preventing the pump part 4 from being removed accidentally from the side recess 3. The pump part 4 includes an inlet pipe 8 which communicates with the interior of the tank 1 through a bushing 7.
Such an arrangement has the following problems:
(1) Since the tank 1 has the side recess 3 as well as the projections 4 formed therein at the outer edges, the tank 1 will be of a complicated configuration. The side recess 3 for receiving the pump part 2 must be formed with an increased accuracy. It is thus difficult to form the tank 1, leading to a reduced efficiency of production and an increased manufacturing cost.
Since the outer edge projections 4 are of a so-called undercut configuration, a molded tank must be removed forcedly out of a mold used. This causes the product to be deformed. It is thus difficult to form the tank 1 with an increased dimensional accuracy.
(2) In order to form the side recess 3 and outer edge projections 4 with a desired dimensional accuracy, the thickness of a material forming the tank 1 is required to be increased up to a predetermined level. This increases the tank 1 in weight.
(3) Since the pump part 2 is located closely adjacent the tank 1, any vibration produced when a motor in the pump part 2 is actuated will be transmitted to the tank 1 to generate a noise.
FIG. 18 is a perspective view of another vehicle window washing system disclosed in Japanese Utility Model Publication No. 64-368. Such a washing system comprises a tank 1 for receiving a washing liquid, a lid member 1b for closing the liquid inlet port 1a in the tank 1, and a pump unit 2 mounted on the lid member 1b at the bottom thereof and including an impeller 2a, a motor 2b and an inlet port 2c. Thus, the lid member 1b defines an integral washer unit with the pump unit 2.
In such an arrangement, it is not required to form any pump receiving recess 3 in the tank 1 as in the aforementioned prior art, since the pump unit 2 is positioned within the tank 1 when the lid member 1b is mounted in the liquid inlet port 1a of the tank 1. Therefore, this window washing system does not possess the three problems as described hereinbefore. However, it raises new problems as follows:
(1) Since the pump unit 2 is mounted on the lid 1b, the position of the pump unit 2 mounted in the window washing system is limited to a range in which the lid member 1b can be mounted on the tank 1. Thus, the pump unit 2 is limited in mounting position and configuration, leading to restriction of the range of permissibility in design.
More particularly, the pump unit 2 must be designed depending on the height h of the tank 1 since it is normally requested that the lid member 1b is placed on the top of the tank 1 and also the inlet port 2c of the pump unit 2 is formed near the bottom face of the tank 1. Therefore, a pump unit designed for a particular tank having a height cannot be applied to another tank having a different height. The window washing system is very limited in application.
Recently, since many different liquid tanks of various different configurations and/or types are being used in various different types of motocars, the above problem becomes very large obstruction in practice.
(2) Since an outlet hose P and a wiring Q to the motor 2b are connected with the lid 1b for the tank 1, the hose P and wiring Q must be slackened sufficiently to move when the lid 1b is mounted on or removed from the tank 1. This also provides a restriction in design.